With the developing complexity of networks and systems for computer communications, there are many applications of multiple processor computer systems in which it is, of course, necessary for each processor to send and receive messages to/from other processors in the system. This type of operation may be designated as "an inter-processor communication net", and such types of communication nets require many different types of communications which may involve:
(1) system initialization status and commands;
(2) system event information such as task completion, notification, and hardware or software interrupt signal information;
(3) signals for assignment of system tasks, jobs, and I/O operations between processing elements;
(4) operator signal inputs and maintenance interface signal conditions involving such operations and halting and/or starting the system into operation.
It is quite commonly known that large multi-processor systems will use a "mailbox" mechanism for purposes of passing messages through specific locations in main memory which routinely stores the instruction microcodes for each processor. However, this type of operation still requires a signalling method wherein one processor may notify another processor that a message or a response is available in that processor's "mailbox". The simple, efficient, "interprocessor communication net" described herein will manage to provide this type of attention mechanism such that a minimum amount of information needs to be transferred.